1. Field of the Invention
This invention relates to diagnostics for computer networks; in particular to diagnostics for identifying problems in layer-2.
2. Description of Related Art
Computer networks are increasingly complex combinations of components. End stations, bridges, routers, and various other devices are combined in order to achieve the desired functionality. As complexity has increased, so has the difficulty in isolating problems in the network. Packets of data transmitted within networks may follow paths that are not readily ascertainable. When a problem occurs in the transmission of packets within the network occurs, it may then be difficult to determine the cause of the problem.
Network managers may use a facility known as a trace in order to help troubleshoot a problem in a computer network. One such trace is known as an xe2x80x9cmtrace.xe2x80x9d Typically, the network manager causes the mtrace to start at the destination of the path that is desired to be diagnosed. When the trace is received by the other end of the path, the node receiving the trace responds. Such a trace typically operates at layer 3 of the computer network.
With the increasing complexity of computer networks, isolating faults in the computer network becomes more important. Therefore, it is desirable to obtain improved methods and equipment for isolating faults and troubleshooting in computer networks.
The invention is directed to a method of troubleshooting a path that includes a source node, a set of destination nodes, and a set of at least an intermediate node in a computer network. The source node sends a packet to an intermediate node in the set of at least an intermediate node. At least a layer-2 intermediate node in the set of at least an intermediate node inserts data into the packet, and the layer-2 intermediate node sends the packet to another node according to information on the intermediate node regarding the path.
According to an aspect of the invention, data includes an identifier of the layer-2 intermediate node. The data may include a medium access control (MAC) address of the layer-2 intermediate node. The data may also include a number corresponding to a time at which the packet traversed through the layer-2 intermediate node.
According to another aspect of the invention, the packet has a layer-2 payload that includes an address corresponding to a node in the set of destination nodes. According to another aspect of the invention, the address corresponding to a node in the set of destination nodes includes a logical link control address assigned to a bridge spanning tree protocol. The address corresponding to a node in the set of destination nodes includes a MAC address, according to another aspect of the invention. The MAC address may include a unicast address or, according to another aspect of the invention, a multicast address.
According to another aspect of the invention, intermediate nodes in the set of at least an intermediate node send the packet to respective intermediate nodes or a node in the set of destination nodes according to a spanning tree algorithm.
According to another aspect of the invention, at least a node from among a node in the set of destination nodes and nodes in the set of at least an intermediate node sends a second message to a network management station, and the second message includes at least a portion of the data.
An embodiment of the invention includes a packet for troubleshooting a path in a computer network. The path includes a source node, a destination node, and a set of at least one intermediate node. The packet comprises an address that corresponds to the destination node and data inserted by layer-2 intermediate nodes through which the packet has traversed.
An embodiment of the invention includes method of troubleshooting a path that includes a set of layer-2 devices and a set of layer-3 devices. A first trace is initiated to cause at least a layer-3 device in the set of layer-3 devices to insert data into a first packet. Based on the first trace, a second trace is initiated to cause at least a layer-2 device in the set of layer-2 devices to insert data into a second packet.
An embodiment of the invention includes a node in a computer network. The node is in a path that includes a source node and a destination node. The node includes layer-2 logic that receives a packet, and, if the packet includes an indicator that a trace is to be performed, inserts data into the packet and sends the packet to another node in the path.